Oxidized saturated fatty acids, containing a hydroxyl or an oxo functionality, have attracted little attention so far. Recent studies have shown that saturated hydroxy fatty acids, which exhibit cancer cell growth inhibition and may suppress β-cell apoptosis, are present in milk. Herein, we present the application of a liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method for the detection and quantification of various saturated oxo fatty acids (SOFAs) previously unrecognized in milk. This robust and rapid analytical method, which involves simple sample preparation and a single 10-min run, revealed the presence of families of oxostearic acids (OSAs) and oxopalmitic acids (OPAs) in milk. 8OSA, 9OSA, 7OSA, 10OSA and 10OPA were found to be the most abundant SOFAs in both cow and goat milk. Higher contents of SOFAs were found in cow milk in comparison to goat milk. Together with SOFAs, ricinoleic acid, which is isobaric to OSA, was detected and quantified in all milk samples, following a “suspect” HRMS analysis approach. This unique natural fatty acid, which is the main component (>90%) of castor oil triglycerides, was estimated at mean content values of 534.3 ± 6.0 μg/mL and 460 ± 8.1 μg/mL in cow and goat milk samples, respectively.

中文翻译：

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液相色谱-高分辨率质谱法（LC-HRMS）测定牛奶中的游离饱和氧代脂肪酸（SOFA）和蓖麻油酸

迄今为止，含有羟基或羰基官能团的氧化的饱和脂肪酸很少受到关注。最近的研究表明，牛奶中存在饱和羟基脂肪酸，这些羟基脂肪酸具有抑制癌细胞生长并可能抑制β细胞凋亡的作用。在此，我们介绍了液相色谱-高分辨率质谱（LC-HRMS）方法在检测和定量牛奶中以前无法识别的各种饱和氧代脂肪酸（SOFA）方面的应用。这种强大而快速的分析方法涉及简单的样品制备和一次10分钟的运行，揭示了牛奶中存在硬脂酸（OSA）和草脂酸（OPA）家族。发现8OSA，9OSA，7OSA，10OSA和10OPA是牛和山羊奶中最丰富的SOFA。与山羊奶相比，牛奶中发现的SOFA含量更高。按照“可疑” HRMS分析方法，在所有牛奶样品中都检测到并定量了与OSA同量的蓖麻油酸和SOFA，并对其进行了定量。这种独特的天然脂肪酸是蓖麻油甘油三酸酯的主要成分（> 90％），在牛奶和山羊奶样品中的平均含量分别为534.3±6.0μg/ mL和460±8.1μg/ mL。